A. Field of the Invention
The Invention relates to a telescopic sight mount for a rifle, specifically a telescopic sight mount for a '98 Mauser rifle.
B. Description of the Related Art
Many rifle designs especially those of military nature were built with quite robust rear sight designs, most famous of these being the K98 Mauser. Over the years many other rifle designs have emulated those of the Mauser. My invention is concerned with the manner in which the K98 Mauser long tangent rear sight base assembly was configured, in particular the top portion of the rear sight base. This base design allowed for the easy removal of the sight blade (55) at the anterior base section and the leaf spring from the posterior of the base. This easy removal was achieved by the machining of upward, inward facing opposing bosses at the anterior of the base. The upward bosses also contained a through hole, in which the bisected upper portion of that hole was centrally located at the thicker lower edge of the inward facing bosses.
There were outward facing, round lateral extensions located at the front of the tangent sight blade. These lateral extensions were then captured by the inward facing anterior base bosses at the upper circumference of the boss through hole on the thicker lower edge of the boss of the anterior of the base. The rounded lateral outward extensions of the sight blade front, captured by the mating upper boss hole circumference, enabled the sight blade to then pivot upwards from the posterior of the sight base and gain elevation if necessary for a longer shot. A movable slider on the sight blade kept the elevation adjustment in place on the sight base.
The leaf mainspring, which extended longitudinally from the posterior of the sight base U shaped spring slot, applied upward pressure against the front outward facing round protrusions of the sight blade. This upward pressure by the mainspring, against the bottom front of the sight blade and ultimately to the upper circumference hole of the inward facing opposing bosses, kept the sight blade in place at the anterior of sight base.
The presence of these base bosses, boss through hole, and U shaped slot at the posterior sight base makes my scope mount invention possible.
The long tangent rear sight did not first appear on Mauser military rifles until after 1900. It soon became the main rear sight. Most new, and Mauser rifles returning to the arsenals for refurbishing were retrofitted with the long tangent rear sight after that date. Total production of Mauser military rifles from 1888 to 1945 is estimated at over 100,000,000. My estimate is that over seventy five percent utilize the long tangent rear sight.
The need for a scope mount to readily replace the rear sight assembly is evidenced by the prices these said guns are fetching in their original condition. A reliable scope mount that can readily be attached to the rifle without in anyway detracting from its original appearance except for the easy removal and later replacement of these said original parts, the sight blade and main spring, should be marketable.
The forward location of the rear sight will require a long eye-relief scope in actual use. These scopes are common and very useful as they do not block the back receiver area of the rifle where bolt manipulation and ammunition loading take place.
As for other related patents that use a preexisting forward sight base in their application, I could only find one, the George McCann (U.S. Pat. No. 2,036,290) scope mount. His patent also utilizes preexisting holes and notches to fasten the mount to the rifle. His 1936 patent utilizes the rear sight base of a 1903 Springfield rifle (Actually a 1898 Mauser in basic design) and the magazine hold catch slot on the receiver as basic points of affixing the rifle. My design is an improvement over the McCann in that his use of the rear sight base slots only fixes at one point in the sight base which provides an unequal purchase of the slots. His capture forces are all in the up direction with a single lever screw turned from the top mounting plate exerting upward pressure of this mounting plate towards the sight base undercuts. The use of upward pressure alone to secure an item will work in the short run but for long term usage a downward force on the mount to the sight is preferable. The McCann design also only fastens at 2 points and there is a fairly long distance between those fastening points, approx. ten inches. Such a long span between fasteners probably caused scope flexing on recoil. My design is far shorter, approx. three inches, and fastened and locked in at three points all within the space of the host rear sight base and all exerting downward force of my scope mount base to the sight base.
I am aware of two other designs (actually only one as they both work on the same principal) that utilize the rear sight base of the K98 as the mounting point for their scope mounts. These products are marketed by Mitchell's Mausers, and the other by B-Square. They both utilize previously stated inward area of the opposing sight base bosses, as the forward fixing point of their scope mounts to the rear sight base, however they do not have the outward facing slots as my invention has on the front scope mount body sides to capture the lower edges of the sight base bosses. Their rear sight bosses only make contact with the said sides of the body at their vertical inward edge. No contact is made with the bosses' lower edge As for lockup at the posterior of the sight base the competition rely on a blind top body tension screw to put upward bearing, reverse pressure upon the back of their scope mount. The screw is not fixed into anything on the sight base. The screw is just exerting pressure on the sight base surface at the relatively small surface area of the screw tip contact.
My lockup at the posterior of the sight base utilizes a threaded T nut which is sized so as to fit in the U shaped slot of the posterior of the sight base. A screw head tension screw then captures the back of my scope mount in a top body counter bored through hole. The screw is fixed into a threaded T nut being held by the U slot of the sight base. Upon tensioning, the scope mount body back is drawn down tightly against the top posterior area of the sight base. In addition the bottom of my scope mount body also contains a slot sized to capture the top edges of the T nut. Upon tensioning, the top area of the T nut is firmly engaged in this bottom slot of my scope mount body. The back lateral forces that occur upon recoil are restricted now by the much broader surface area of the T nut and not just the relatively narrow area of the point contact of a tensioning screw. Recoil forces from a rifle cartridge generate approximately fifty thousand foot pounds per square inch force. This force extends mostly in a longitudinal and lateral direction in relationship to the bore. In order for these forces to be properly contained and absorbed a broader surfaced capture system is needed than a simple blind reverse pressure screw as featured on the competition's offerings.
The other Mauser 98 tangent rear sight scope mount that I am aware of is the ZF41. The scope mounting system was developed by Germany during WWII. From my inspection of one of these scope mounting systems mounted on a Mauser 98 rifle, I feel that there is no crossover whatsoever. The system replaces the removable second part that appears on some of the rear sight bases. The area that is removed is then replaced with a new part designed to fit in removed area. The mainspring and sight blade are then returned to the rifle on the new part and function as previously stated. The ZF41 telescope mounting solution is then arrived at from side appendages on the redesigned replacement new part. Since the anterior rear sight bosses and a T nut at the posterior of the sight base are not involved in the ZF41, I see no problem with the claims of my design.